Method and means for facilitating engine starting



1951 G. R. ERICSON METHOD AND MEANS FOR FACILITATING ENGINE STARTING 2SHEETS-SHEET 1 Filed March 5, 1945 IN VEN TOR.

CYL.2.

FIC.3.

Nov. 13, 1951 G. R. ERICSON 2,574,694

METHOD AND MEANS FOR FACILITATING ENGINE STARTING Filed March 5, 1945 2SHEETS SHEET 2 IN V EN TOR.

Patented Nov. 13, 1951 METHOD AND MEANS FOR FACILITATING ENGINE STARTINGGeorge R. Ericson, Kirkwood, M0,, assignor to Carter CarburetorCorporation, St. Louis, 'M0., a corporation of Delaware ApplicationMarch 5, 1945, SerialNo. 581,097

8 Claims.

This invention relates to improvements in internal combustion engines,and more particularly to a method of supplying combustion air tofour-cycle diesel engines, as high speed automotive diesel and the like,and to novel and effective provisions for controlling the supplying ofair to such engines, so as to promote and greatly facilitate positiveand relatively quick engine starting.

.A principal object of the present invention is to providea method ofsupplying combustion air to engines of the character indicated, in whichcylinder induction of air in the engine starting period, is determinedsuch as to aiTord a high velocity air flow toward the cylinder uponopening of the cylinder intake valve, and further, such as to produce inthe cylinder at the beginning of effective compression consequent tointake valve closure, a volume of combustion air characterized by apressure at least approximating atmospheric pressure and a temperature.exceeding that of the atmospheric air source, whereby to determine theultimate pressure and temperature of compression of the cylindercombustion air, at values sufficient to promote quick engine starting.

A further principal object of the invention is to provide in an engineof the character, indicated, an improved cylinder air induction orintake system including automatic intake control means and a timing ofcylinder intake valve operation to include valve closure at apredetermined time following termination of the cylinder suction cycle,wherein the system according to the present improvements, is effectiveduring the engine starting period, to determine and control cylinderinduction of air in a manner to assure relatively high cylindercompression pressures, as well as high compression temperatures, in theseveral cylinders at the end of cylinder compression, whereby to promotepositive and quick engine starting, as Well as relativel rapid enginewarm-up and consequent early attainment of normal running conditions.

Objectively to the foregoing, the automatic air intake controlprovisions in the present induction system, include valve meanseffective during engine starting when piston speeds are relatively low,to promote high cylinder suction and consequent high depression in thesystem, and to establish high velocity .air intake to the enginecylinders. As .a result of the latter .in particular and further inconsequence of intake valve timing such that valve closure occursfollowing cylinder suction, as early in the cylinder compres- I quickengine starting.

sion cycle, there will obtain in each cylinder at the time of intakevalve closure, a volume of combustion air under a pressure atleastclosely approaching, but normally equal to or even appreciablyexceedingatmospheric pressure. Consequently, the ultimate or finalcylinder pressure and temperature of compression obtaining at the end ofcompression in each cylinder during the engine cranking period, will besumciently high to facilitate quick engine starting through resultingpositive ignition and combustion of the enginefuel.

Another important object of the invention resides in the provision of animproved air induction system of the character hereinabove indicated,wherein the intake air supplied thereby to the engine cylinders duringthe engine starting period in particular, is warmed to an appreciabledegree, so as further to facilitate positive and In the present system,advantage is taken of the kinetic energy possessed by the high velocityintake air flow established in the engine starting period, as a sourceof heat for warming the intake air, the heat energy for this purposebeing derived from the kinetic energy of the air flow as an inherentresult of the character of air intake control afforded by the presentimprovements.

A further object resides in a division of air supply to the cylinders ofa multi-cylinder engine of the character indicated, wherein thepresently improved character of cylinder air induction is determined andcontrolled separately as to each of several groups of cylinders, so thatthe intake valves of each cylinder group may be operated in relativelytimed relation such ,as to avoid any substantial overlapping of the openperiods thereof. In consequence of the latter, the functioning of thepresent cylinder air induction system is enhanced to a material degree,since at any given time, only one of the cylinders of a group isundergoing .the full air induction cycle as herein provided, thusavoiding air flow interference and inaccuracy of air induction controlwhich otherwise would tend to occur.

A still further object is attained in respect to the presently improvedair induction system having valve means effective during the enginestarting phase, to determine high velocity air flow to the enginecylinders in the cylinder suction cycle, by the provision of controlfacilities operable responsively to a condition of air flow determinedin a region of the supply passage in theinduction system, and to acondition of the engine obtaining during warm-up and as normal runningconditions are attained, to condition said valve means for permittingair flow through the induction system and to the engine cylinders, involume and rate of fiow fully adequate to supply the engine under normaloperation throughout its speed and load range.

Other objects and advantages afforded by the present improvements willappear readily from the following description of an embodiment of,

the invention, as illustrated in the accompanying drawings, wherein:

Fig. 1 is a diagrammatic plan-elevation partly in section, of amulti-cylinder engine having the presently improved air inductionprovisions embodied therein;

Fig. 2 is an enlarged fragmentary side elevation of the air inductionmeans, with parts thereof shown in section;

Fig. 3 illustrates diagrammatically, the character of cylinder intakevalve timing provided by the present improvements, showing in particularthe relative open periods of the several cylinder intake valves;

Fig. 4 illustrates a modification in the air flow control valve meansemployed in the induction system; and

Fig. 5 is an enlarged somewhat diagrammatic vertical sectiontransversely through a cylinder organization of the engine, illustratingthe delayed closure of the intake valve thereof following termination ofthe cylinder suction cycle.

Fig. 6 is a detail view showing the operative connection of the controlvalve elements embodied in the present induction control system.

While it is presently preferred to illustrate the improved air inductionsystem in application to a six cylinder four-cycle diesel engine asindicated generally at ID in Fig. 1, it will become obvious as thedescription proceeds, that the method of cylinder air induction and theinduction system of the character now provided, may be applied ingeneral to single or multi-cylinder, four-cycle diesel engines, and withgreat advantage, to automotive diesels.

Referring first to Fig. 1, the engine I shown somewhat diagrammaticallyand partly in section as to the cylinder head portion thereof, includessix cylinders shown in broken lines and desigated from right to left inthe figure in accordance with the preferred cylinder firing order, c.

as cylinders I, 5, 3, 2, 6 and 4. Associated with the cylinders is acylinder head structure indicated by numeral I, providing air admissionand exhaust ducts or passages I2 and I3 respectively, for each of thecylinders. Controlling air admission to the cylinders through the ductsI2, are intake valves indicated diagrammatically at I, 3', 2', 6 and 4'corresponding to the cylinders in that order, while the exhaust ducts I3are under the exhaust discharge control of similarly shown exhaustvalves 5", 3", 2", 6" and 4". The exhaust and intake valves may beactuated in properly timed relation to the engine operating cycle, inany suitable well known manner as by an engine driven camshaft indicatedat I4 in Fig. 5, operating at one-half engine speed in the presentfour-cycle engine, and providing an exhaust cam l5 for each exhaustvalve, and a cam l6 for each intake valve. Operation of the valves fromthe cams may be effected as by rocker arm and push rod devices such asthe push rod I! and rocker arm I 8 shown in the diagrammatic view ofFig. 5, arranged between cam I6 and one of the cylinder intake valves,as for example, the intake valve 2' of cylinder number 2 shown in thefigure. However, in regard to the timing of intake valve operation andparticularly with respect to the time of valve closure in the engineoperating cycle, such is here determined in accordance with theobjectives of the presently improved induction system, to include adelay in intake valve closure following the cylinder suction cycle. Thiswill be referred to more fully hereafter.

The cylinder exhaust ducts I3 communicate with an exhaust manifold I9which may be of conventional character, extending to a suitable point ofexhaust discharge, while the intake ducts I2 receive air through anintake manifold 20 embodying air intake control provisions according tothe present invention. As appears from Figs. 1 and '2, manifold 20provides an air intake tube or pipe 2| projecting from the midportionthereof and terminating in a relatively wide-mouth atmospheric inlet 22.The pipe 2| thus determines opposite corresponding manifold sections 23and 24 individual respectively (Fig. 1), to the intake ducts I2 ofcylinders I, 5, and 3, and to the like intake ducts I2 of cylinders 2, 6and 4. For purposes herein and as to claim definition, the manifoldsection 23 together with the associated cylinder ducts l2 and the inletpipe 2!, comprise means affording the cylinder air supply or intakepassage to cylinders I, 5 and 3, while the manifold section 24 with theassociated cylinders ducts I2 and inlet pipe 2|, constitute alikepassage for cylinders 2, 6 and 4.

As objectively indicated hereinbefore, it is the principal purpose ofthe present invention to provide a method of cylinder air induction andto afford control of engine combustion air intake, such as to promote orcontribute materially to quick engine starting, and to attain thereby,rapid warm-up and an early conditioning of the engine for normal runningoperation. In fourcycle diesel engines and especially in connection withautomotive diesels which may be subject at times, to conditionsparticularly adverse to quick engine starting, as for example, coldweather or when the engine has remained idle or in an inoperativecondition for a long period, the attainment of positive and relativelyquick starting during engine cranking and when piston displacement isrelatively slow, may be greatly facilitated by increasing to asubstantial degree, the air pressure and temperature of compressionobtaining in each cylinder at the end of its compression cycle. Such isaccomplished according to the present invention, by novel and effectivecombustion air intake control provisions presently to be described, andby a predetermined timing of cylinder intake valve operation of acharacter to appear, functioning during the engine starting period todetermine combustionair filling of each cylinder undergoing itsair-induction cycle, to a degree such that the cylinder air pressure atthe time of intake valve closure will substantially equal or evenappreciably exceed atmospheric pressure. Also and as an inherenI; resultof the present provisions, the

cylinder air temperature at such time, will exceed to a material degreethe temperature of the atmospheric air admitted to the induction systemat the inlet pipe 2|. Consequently, with combustion air at or aboveatmospheric pressure and at an appreciable temperature, present in thecylinder at the beginning of the effetive compression cycle, as uponclosure of the intake valve, the air pressure and temperature ofcompression obtaining at the end of the compression cycle will, attain.such relatively? high values". as I, I

will"; promote? positive: and: quick fuel ignition. as

fliel isr injected into the cylinder,- to the end. of

section .24 and near; the zone: of. juncture thereof with: inlet-pipe;21-. (Fig.2), is; acontrol. valve element; 25,.preferably; alplatea-valve Ofl the butter-fly type;- .which ismounted:ona1pivotwshaft 2.6 somewhat eccentricallyz relatedathereto;Sime Harm-located; within manifold section 23;:isza like valvepelementz2:1 pivotedmn; a. shaft.28:-.-"Which= is eccentrically related; to thevalve; Thepivot shafts;;2.6 and 28-; proj ectroutwardly'r of the maniefold and onythezsameside; andito shaft-*zfieissuitably-secureiayalvecontrol lever 2.3a Anarm 30-:- (Fig. 6) secured to: the: proj eoting,portion of shaftl2'8, isconnected; to: lever; 29 .a by atlink; elce ment,31-lpivoted at its-ends tothe arm and;,z1ever.;

asshown: Thusithe valves 25'1-and 2.1 are. con-.-

nectediintandem, andghence constrained to; conjoint correspondingopening and closing-mover ments.

In: the normal; non-operating condition; ofthe? engine andalso. during.theengine startin neriod as will be: morefully; appreciated; hereafter,-the: control; valves are; retained; in manifoldeclosing, positions as;-shownv in- Fig. 2, by control; means whichacccordingto=presentpreference, is? of an automatic,thermally-responsive: character; Innresent eXa mp1e,.,Sll0hgCOI1tr01means is; providediby a spiral-formbiemetallic thermostat or;

thermally-sensitive membeniz; which: isenclosed," preferably in. agenerally circularor-- cylindrical.

housing: 33 carried-by manifold 20, and has its; innenend 34. secured toan extension: of valve; shaft-28-,- the. latter extending substantiallyaxially within-housing; 33. The opposite end SsEeof; mem ber. 3-2isfixed; to; the housing; as .by; p;ini 3.6:, so that the thermostatmemberthus: imposes through shaft- 28, a. constantbias on the:tandemvalves 25 and. 21-. When sufficiently cooled; or in' a coldcondition, the spiraleoontractionof the; member serves-todisposethevalves in the-mani fold closing positions shown, and through proper.selection of the member asto its spring-forcecharacteristics, itis.determined to be effective; its cold condition, to hold the controlvalves closed againstthe valve opening influence im posed on the valvesby means, presently tow ape. pear. Moreover; since the valves: 25. and;21". are eccentrically pivoted so as to .be subject in avalveopeningdirection, to; manifold depression. posterior: to; the valves, the valveholding; forceof the. thermostat member so selected, must be;-sufilcient to prevent: openingof the valves; in, response toenginesuction and consequent mania-- fold. depressions of theorderattained,- during;

enginestarting as this will appear. hereinafter soias. to permitattainment, ofthe character; of

air intake. control; afforded; by the present im provements. intheuengine starting period.

Upon cranking of. the engine in the starting:

phase, which may be effected in conventional: 6

manner, as by. a, cranking motor (not shown) turning over the engineat arelatively low speed-, cylinder induction of air; insufiicient; volumeto: support fuel combustion in the cylinders,v is: determined andicontrolled in part; according to; the presently'improved?inductionsystem, by'the pl'ate valves 25 and 21, each of which bypresent pref; erence, has one or: more ports ororifi'cesprovidedtherein. here shown for example, valve wisprovided withan orifice 31and-valve- 21 alike orifice: 38; theseorificesibeingsof: calibratedarea,- predetermined; according. to the engine to whichthesystem-isapplied, anditoethe characte'n of air, control tobe-attained-z Since the valves preferably are fully closed at. enginestarting; the orifices ofi'er at. such time substantially.- the solea-irs-flow communications: between the" intake pipell and the manifoldsections-or branches 2.3 and. Consequently, the portedevalveswhen. inclosedtpositionsat: engine starting, thus: introduce as to each manifoldsection, an, intake air-flow constrictionianterior toethecylinder intakepas.- sages communicating with the section. While; it. ispresentlypreferred for reasons of greater accuracy of control, to. employcalibratedorifices in the plate valves. for determining" the desireddegree. of, passage constriction in. the closedposie tion of 'eachvalve,itwill. be appreciated; that-approximately, the same result. may: be:obtaine with. valves devoid; of, ports or: orificestlhcltein, suita lprovisions. not here showm asfor pro-- ventinacomple e losur'e of hemanifol se tion y' uch-va1ves..so, as leav a ma pen n about. each valveand of, a al; ar v e iva entto that determined forthe orifice (3.7 or38;) uti ized acco di o h p n a ran e en Considering the-manifoldsection 24.; related to cylinders 2,6; and; 4, and havingthecor-rtrohvalvev 25; therein, when any one; of. these cylinders, ascylinder number 2 for example, is undergoingl -5? uot nora e t its ntakelv 2. fu l-open; (Fig. 5;), the resulting cylinder suction tendstoproduce a corresponding; depression in. the-manhiold section 2!;posterior to valve 25;.- Since-the valve when in closed;positiomaffords, only asrnall opening, asthe; valve orifice 37y betweenthe; ate. snher a r. n ke p p 2 and. the manifo d section, the cylindersuctionandconsequent; sue= tion or depression in; the man-ifold are thusverymater' a y n r e reaching a is-h alu the piston 39 (Fig. 5)undergoes its; maximum; rate; of displacement in: the suction stroke; Incons qu nce of: h hi y i der; an an fo d depression thus: affiorded,there is induced.

; through the valveorifice 31:, ahigh. velocity in;-

fiow of combustion. air from; the supply pipe 2l-i,. he air he c r vlingi toward the cylind r. 2.. at; high. velocity attenuated, onlyslightly by: reason of. frictional losses in, the;manifoldandcylinderlntakeduct I}. As the piston approaches andi attains;the end of; its suction stroke, the velo ci-ty of airintake to thecylinder tends to decreasesat. a proportionate rate, andis; additionallyreduced; by reason of the rising pressure head: as; air fiflle ing ofthe cylinder approached. However, and for a purposepresently to appear,the; degree of manifold constrictionafiorded by the valve 2,5.as:determined by. proper selection of; the area. of valve orifice-31, is-such as toaffordat'l'east. a low velocity cylinderintake of; air; asthe piston attainsthe end of its suction stroke.

Continuing, as, thenature and. function of; the presently:improvedinduction system with. regard to cylindersiz, 6 and 4", butwitharespecttoi cylinder number 2 for present example,v while thereremains a tendency'for:furthersli'ght cylin der: intakeof air. as thepiston reachesthe end of its. suction stroke, nevertheless at such timethe pressure at the air thenin the cylinder, will approach in valueatmospheric pressure. since-a purpose of the-present invention-is tea-Iford the attainment of ultimate highcylinder compression pressures forpromoting quick en--.-.

gine starting, further provision ismade through 75" timing of: intakevalve operation, assume sup However,

' cylinder firing order indicated in Fig. 1.

ply of combustion air in the cylinder at the beginning of the effectivecompression cycle occurring when the intake valve is fully closed, whichwill be under a pressure at least closely approximating, but preferablysomewhat in excess of atmospheric pressure. Accordingly and asillustrated in Fig. 5, the intake valve operating cam [6 on a camshaftM, the latter being suitably driven at one-half engine speed preferablythrough an operating connection (not shown) from the engine crankshaftindicated at 40, is provided with a cam-lobe 4| of such form andpredetermined angular extent and so positioned relative to the camshaft,as to be effective through push rod I1 and rocker arm 18, to produce afull-open or nearly full-open condition of the cylinder intake valve atsubstantially the beginning of the suction stroke of piston 39 (theopening displacement of the intake valve may begin some few degrees ofcrank travel before top dead center of the piston), and to maintain thevalve in open position throughout the ensuing suction period and duringan initial period of the piston compression stroke. In the presentexample, the extent to which intake valve closure is delayed beyondtermination of the suction period, is determined in accordance with theherein described characteristics of velocity intake afforded by thesuction increasing control valve 25 having the calibrated orifice 31therein, and is such that valve closure will occur relatively early inthe piston compression stroke, as at a point therein represented bypiston crank travel of about 60 degrees from the piston position atbottom dead center. This is shown by the diagrams of Fig. 3 whichrepresent by shaded arcs, the relative timing and duration of intakevalve opening for the present four-cycle six cylinder engine having theWith reference to the right hand diagram thereof, the innermost arcdesignated by the reference indicia Cyl. 2, concerns the intake valve 2'of cylinder number 2. As there shown, the valve attains an open ornearly full-open position at point 42 corresponding to the beginning ofthe piston suction stroke, and continues open through the diametricallyopposite point 43 corresponding to the piston dead center position atthe end of its suction stroke, to the point 44 of actual or substantialvalve closure, the latter corresponding to a position of the piston inits compression stroke, determined by crank travel through approximately60 degrees from its dead center positioning of the piston at the end ofthe suction cycle.

In consequence of the'delayed valve closure thus effected, air intaketoward the cylinder, may continue as the piston attains the end of itssuction stroke and starts upon its return stroke in the followingcompression cycle, so long as any degree of suction remains between thecylinder and the ported control valve 25. As all suction effortdisappears, the volume of air in the cylinder and in the air supplypassage as hereinbefore defined, posterior to valve 25, will beat apressure at least very closely approximating atmospheric pressure.However, in the present induction system and by reason of thepredetermined area of the valve orifice 31 and the furtherrelativetiming of intake valve operation as will presently appear, thesubstantial balancing of cylinder air pressure with atmospheric pressureis ob tained at a time following the end of the suction cycle, butappreciably before intake valve closure. Consequently, following theattainment of pressure balance and as piston displacement con- 3 tinuesearly in the compression cycle, the-piston will tend to effectcompression of the cylinder air against the volume of air in the intakepassage posterior to the valve25, tending thereby to reject air throughthe valve orifice 31. However, by reason of the predetermined relativelysmall area of the orifice, the rejection of any material portion of theair in the intake system posterior .to valve 25 in the compressionperiod prior to intake valve closure, will be thereby impeded to anappreciable degree. Accordingly, the cylinder intake system is thusconditioned at this time in the engine cycle, to permit compression ofthe air in the cylinder, so that when closure of the intake valve occursto determine the beginning of the effective cylinder compression cycle,the cylinder air will be under compression appreciablyabove atmosphericpressure. Hence the presently improved induction system may becharacterized as one which affords at engine starting in particular, adegree of' cylinder supercharging, to the end of promoting quickstarting of the engine.

The foregoing may be and is here greatly facilitated by a relativetiming of the intake valves associated with cylinders 2, 6 and 4supplied from manifold section 24, such that there is little if anyoverlapping of the open periods of the intake valves 2, 6' and 4'.Stated otherwise, intake valve timing as to the'above cylinder group, issuch that only one cylinder at a time is subjected to the full airinductionand pressure increasing action of the system, obtaining throughthe cylinder suction cycle and about the first 60 degrees of crankmovement in the following compression cycle. Hence effective functioningof the induc-' tion system as hereinabove described, is thus determinedas to each cylinder of the group with-' out disturbance which wouldotherwise appear under acondition-of any appreciable overlap of valveopening periods. Referring again to Fig. 3, the right hand diagram inthis figure illustrates by shaded arcs the presently preferred relativetiming and duration of intake valve opening for cylinders 2, 6 and 4,obtained by determining the angular extent of the intake valve operatingcams (as hereindescribed for cam H5 in Fig. 5), and the relative angularpositioning thereof on camshaft I4. As there shown, the are designatedby the indicia Cyl. 4, indicates in clockwise direction, a full ornearly full-open condition for the intake valve of this cylinder atpoint 45, corresponding to the beginning of the suction cycle, and itscon tinuously open position for about 240 degrees of crank travel (thusbeing open for approximately the first GO'degrees of crank travel in thecom-i pression cycle) to a point 46 of valve closure. At

the latter point, the intake valve of cylinder 5 opens or approaches afull-open position and continues open for the succeeding 240 degrees ofcrank travel, as indicated by the are designated Cyl. 6, closing atpoint 42. intake valve of cylinder 2, this opening or approachingfull-open position at point 42" and continuing open as represented bythe are designated Cyl. 2, for the next succeeding period of 240 degrees of crank' travel, closing at point 44. Thus it will appear thataccording to the presently pre-' ferred example, these valves do notoverlap beyond a very negligible amount, as'to their open" periods ineach four cycle operation of theengine., 4

With respect now to cylinders l, 5 and 3, and

the manifold section 23 associated therewith and having the controlvalve 21 therein, the induction;

Similarly with the system per t s i exa t h sam ma n hereinabovedescribed in connection with cyline der 2, 6 and 4,. Valve 21, as beforenoted, is ,pr

vided with orifice 38 which is of calibrated area corresponding to thatof the orifice 3 in valve 25, while the intake valves of cylinders l,and 3 are relatively timed so as, toavoid any material overlapping ofthe open periods, thereof, and are operated such that each when. openedat the beginning of the suction period, remains open through 240degreesof crank travel. lhe open relationship of these intake valveswhich, corresponds to that hereinabove. described for the in-: takevalves of cylinders 2, 5. and 4, is. shown by the left hand diagram inFig. 3., wherein the intake valve. of cylinder l indicated as totheextent of its open period by the shaded arc designated Cyl. l,, opensat point 48 corresponding to the be:v

timing and duration of intake valve opening.

such that each valve opens at the beginning of the suction cycle andremains open through and beyond the suction period, to closure at apoint of piston displacement relatively early in its compression stroke,as that determined by about the first 60 degrees of crank travel fromits bottom dead center positioning otthe piston,

. the time otvalve-openin relative to the suction cycle, as well as theextent to which valve closure is delayed following termination of thesuction cycle, may be varied within limits so as to suit valve timing toany given engine of the character indicated, intended'for usual orparticular operating conditions, yet such as to afford the char.- actorof engine starting air induction control provided by the presentinvention. Also, it will be now appreciated that the present division ofthe intake manifold system into two sections each associated with agiven group of cylinders, as no more than three thereof in' the presentexample, and each having'a ported control valve therein functioning ashereindescribed, greatly facilitates the attainment of the character ofduction of air relative to more than one cylinder of the associatedgroup, were permitted to occur at the same time or successivelyinperiods overlapping to any substantial degree.

The presented improved induction system is fully effective during theengine starting period, to determine in each cylinder at the time ofintake valve closure, a volume of combustionair under a pressure atleast closely approximating atmo pheric pr ssur b normally und r f 16sirable degree of super-atmospheric pressure. However, the air pressureat such time" may be even further increased by effectin closure of themanifold valve orifices 31 and 38 at a point in the p ration oi theinduction system when there: exists, a tendency for air rejectionthrough the orifices from the engine side of the control valves, as.the, latter tends t e ult b reason of pis n displacement early in itscompression stroke as hereinbefore described. To this end, each of themanifold cont valves a d may be provided with a inwar y o eni al em t orcheck valve -52, as shown in Fig. 4 at the orifice 31- of valve 25,tensioned toward orifice: closing p n b a suitab e i tv prin 53 whichpreferably, is of a character such that it will offer little orimmaterial resistance to the opening of the valve element in the airintake function of the system during engine starting Thus it will appearthat, when the air pressure on the engine side of the manifold valve, issuch as to result in a tendency for air rejection through the valveorifice, the valve 52 will respond in the direction to close theorifice. Consequently, the

a volume of air thus trapped in the air supply passage .and in thecylinder then open to the passage, may be effectively compressed such asto determine in the cylinder at the time of take valveclosure, a volume,of air characterized by an appreciable super-atmospheric pressure.

The present induction system is characterized further by an importantfunction in aid of quick engine starting, in thatas a result of thechar: actor of high velocity air intake to. the engine cylindersafforded by the manifold control or choke valves 25 and 21. having thedescribed cali-. brated orifices therein, the air is warmed almost fromthe start of cylinder-intake, andbecomes increasingly heated as intakecontinues and as cylinder air pressure rises prior to intake valveclosure. As will be understood, the intake air under high velocity flowduring a major portion.

of the cylinder suction cycle, enters the cylinder against an increasingback pressure developing therein as the cylinder fills with air.Consequently, the increasing resistance to velocity flow imposed by thelatter, results in a conversion of the kinetic or velocity energy of theentering air, to heat energy which is absorbed immediately by the air inthe cylinder as well as the metal of the exposed piston head andcylinder walls. As thus heated during the engine starting period, thecylinder air normally will attain'a very appreciable temperature in eachcylinder at or about the end of the suction cycle thereof, and at suchtime may reacha temperature of the order of 30 degrees Fahrenheit abovethat of the atmospheric air admitted to the intake pipe 2!. Moreover, asthe cylinder air pressure rises during the early stages of pistondisplacement in its compression stroke and up to the point; of intakevalve closure, the air is heated to an additional extent as a result ofthe degree of air compression then obtaining. Hence, at the beginning ofthe effective compression cycle, as when'the intake valve is closed, thevolume of combustion air then in the cylinder, will be characterized notonly by. a super-atmospheric pressure, but importantly to enginestarting, by a temperature very considerably above the temperature ofthe atmospheric air source, as the gradually toward full-open positionsto condition the intake system for unrestricted air intake normallyrequired during engine running when the rate of piston displacementgreatly exceeds that obtaining during engine cranking in the startingperiod. Opening of the control valves may be and is here attainedautomatically and in response to engine warm-up and air intakeconditions obtaining as the engine approaches normal operation.Referring to Fig. 2 in particular, the thermostatic element 32 whichwhen cold, serves to dispose and hold manifold valves 25 and 21 in theirclosed positions, is subjected to air heated by the engine exhaustgases, so as to produce an expansion thereof serving to turn pivot shaft28 in the direction (counter-clockwise as observed in Fig. 2) to swingthe connected control valves toward full-open positions in the manifoldsections 23 and 24. Air flow into contact with the thermostat isafforded by manifold suction, which may be applied in the thermostathousing 33 through a suction connection 54 in tangential communicationwith the interior of housing 33, and extending to a point preferably inthe manifold throat opposite the intake pipe 2 l. The suction thusimposed in housing 33, is utilized to induce intake of atmospheric airthrough an opening or port 55 in a heater or stove 56 arranged inair-heating relationship to the engine exhaust manifold I9, and thencethrough the stove and a conduit 51 to housing inlet 58 enteringtangentially as shown. Air discharge from the housing 33 is effectedthrough the suction connection 54 into the manifold. It will appear thatby reason of the opposite tangential intake and discharge openings tothe housing 33, air increasingly heated in stove 56 by heat-transferfrom the exhaust gases in manifold H! as the engine warms up, and drawninto and through the housing 33, will traverse the latter in a swirlingor turbulent manner. Consequently, the heated air is thus caused to flowabout and in contact with all surfaces of the thermostat 32, whereby toassure a positive and rapid response of the thermostat in its expansionto open the manifold valves. As the engine assumes and continues normaloperation, the induced exhaust-heated air flow Will continue through thethermostat housing, whereby to maintain the thermostat in expandedcondition so as to hold the valves 25 and 21 in their open positions. Itwill be noted of course, that during engine cranking, some degree of airflow is induced through the thermostat housing, but since such air isthen at atmospheric temperature, and further, since the thermostat 32 ashere employed, is determined to be responsive in the expanding directionbeyond its cold contracted position, only to an appreciable temperature,as that of air heated by engine exhaust gases under discharge throughthe exhaust manifold, the thermostat will remain in contracted conditionuntil appreciable exhaust heating of air occurs in stove 56.

In order to assist valve-opening by the thermostat as it is heated inthe engine warm-up period, as well as to assure valve-opening movementand retention of the valves in open positions should the thermostaticelement 32 fail for any reason to function properly or rapidly enough tocondition the intake system for normal engine operation, it is presentlypreferred to include a pneumatic or suction-operated device normallyworking in conjunction with or supplementing the action of thethermostat, to open and hold open the manifold valves 25 and 21. Asshown in Fig. 2, a cylinder 59 suitably supported (not 12 shown) as onthe intake manifold 20 or the inlet pipe 2| thereof, has a piston 60therein which is connected by piston rod 6! and link 62 to themanifold-valve operating lever 29. One side of the piston as the headsurface 63 thereof, is exposed to atmospheric pressure through an airopening 64 in the cylinder cap 65, while the opposite piston headsurface 66 is subjected to subatmospheric pressure or suction induced inthe cylinder from an appropriate point in the engine air intake passagesor manifold structure. According to present preference, the intake pipe2| is formed to provide a suction-compounding Venturi assembly includingsubstantially concentrically related Venturi passages 61, 68 and 69, anda lateral passage 10 terminating in a suction port H preferably in thethroat 12 of the inner most Venturi passage 69. Passage ID as appears,-is connected through pipe or conduit 13, with the interior of cylinder59, whereby suction may be induced in the cylinder in response tosuction effort applied at port H. are so proportioned as to offer nomore than a minimum or immaterial restriction to the intake air flowrequired under warm-up and normal running conditions of the engine, andto produce under starting conditions when manifold valves 25 and 21 areclosed, a suction effort at port H which is insufficient to causesuction displacement of piston 60 against the resistance offered bythermostat 32 in its contracted position. However, as the engine beginsfiring and warms up, and the valves 25 and 27 move toward open positionsunder the influence initially at least, of the expanding thermostat, thesuction effort at Venturi port 'H resulting from the air intake throughthe venturis at the increased rate then obtaining, will becomeincreasingly pronounced such as to induce a suction in the cylinder 59amply sufficient.

to cause piston displacement in the direction to open the manifoldvalves 25 and 21. Thus the suction-operated device is fully effectiveunder the latter conditions, not only to assist valveopening by thethermostat, but to assure opening of the valves as the engine attainsnormal operation, the device to this end being capable of actingindependently of the thermostat once the valves 2-5 and 21 move beyondmanifold-closed positions to an extent permitting increased air intakeand a consequent suction at port H of an order sufficient to efiectdisplacement of piston 60 against any lagging resistance offered by thethermostat 32.

It is presently preferred to provide additionally, a control connectionbetween the control valves 25 and 21 and the engine fuel control orthrottle device, capable of opening the manifold valves.

independently of the thermostat and pneumatic devices hereinabovedescribed, beyond the enginej As diaidling position of the throttlingdevice. grammatically illustrated in Fig. 1, an engineoperated fuel pumpassembly indicated generally at 14, and which may include fuel pumps ofwell-known or conventional character individual to the several enginecylinders, is provided to deliver fuel under pressure to cylinderinjection valves 15 of conventional air-less injection type;

The fuel pumps (not shown) in the assembly 14 may be arranged so thatfuel-quantity delivery by the pumps may be controlled by a singlethrottling device (not shown) as for regulating engine speed and poweroutput under varying load conditions. Actuated coextensively withoperation of the throttling device, is a lever l6,-

to the end of which is pivoted one end of a link 11. The opposite end oflink 11 is formed to pro- The Venturi passages.

i3 videa slot 18 of suitable extent, to receivfe'a pin 19' carried atthe endof an extension of valve lever 29, thereby providing alost-motionconnection between the lever and throttle link.

With the'valves-25 and 21 inclosed position and the throttle operatedarmor lever 76 inthe po full-open positions of the valves, when thepin1-9 will have been displaced substantially to the opposite or outer endof the link slot 78. However, if for any reason the throttle should beoperated inthe direction to increase fuel delivery at a time when thevalves2'5 and 2'! are in closed 3 positions or only partly open, thethrottle-operated arm 16 then turning in a counter-clock wi'se directionas viewed in Fig. 1, will effect through link" and pin 19, openingmovement ofthe valves 25- and 21 to a corresponding extent. Theimportance of thepresent throttle connec- 'tion with valves 25 and 21resides in the independent control of the latter as afforded thereby, soas to assure during engine operation, an open condition of the valves atleast corresponding to throttle positions, in the event the thermo statand pnuematic devices fail for any reason to effect suflicient openingof the valves as the engine warms up and attains running operation.

It is to be understood of course, that the foregoing is intended to beillustrative of the invention and not limiting, as all suchmodifications as come within the spirit and scope of the appended claimsare here contemplated.

I claim:

1. In combination with an internal combustion engine of the characterdescribed, having a cylinder air supply passage provided for the supplyof combustion air only, to the cylinder, an intake valve in control ofcylinder communication with the supply passage, control means in thepassage effective solely in the period of engine cranking, such as todetermine cylinder induction of air at high velocity toward the cylinderafter opening of the intake valve, and intake valve operating meansadapted to delay intake valve closure to a time following termination ofthe cylinder suction cycle, said control means acting in conjunctionwith the delayed intake valve closure, to determine in the cylinder atthe time of intake valve closure, a volume of combustion aircharacterized by a pressure at least approximating atmospheric pressure.

2. In combination with an internal combustion engine of the characterdescribed, having 9. cylinder air intake passage provided for the supplyof combustion air only, to the cylinder, an intake valve in control ofcylinder communication with the intake passage, engine operated meansfor actuating the intake valve, adapted to open said valve in thecylinder suction cycle and to delay closure thereof to a predeterminedtime following the end of the suction cycle, and a ported valve elementin the intake passage effective in the period of engine starting todetermine cylinder induction of air at high velocity toward the cylinderupon opening of the intake valve, said valve element serving incooperation with the delayed closure of the intake valve, to determinein the cylinder at the time of intake Ell valve *clousre, a volume ofcombustion air under a pressure in excess of atmospheric pressure.

3. In combination with an internal combustion engine of the characterdescribed, having a cylinder air intake passage provided for the supplyof combustion air only, to the cylinder, an intake valve in control ofcylinder communication with the intake passage, engine operated meansfor actuating the intake valve, adapted to open said valve in thecylinder suction cycle and to delay closure thereof to a predeterminedtime following the end of the suction cycle, and a ported valve elementpositionable in the intake passage in theperiod of engine starting, toafford a constriction therein of a predetermined order such as todetermine cylinder induction of air at high velocity toward the cylinderupon opening of the intake valve, said'valve element serving therebyan'din cooperation with the delayed closure of the intake valve, todetermine in the cylinder at the time of intake valve closure, a volumeof combustion air characterized by a pressure in excess of atmosphericpressure and a temperature above that of the atmospheric air source.

4. A fuel burning engine of the four-cycle type having a cylinder, apiston, inlet and outlet valves for 'saidcylinder, a crankshaft foroperating'said piston, means driven by said crankshaft for operatingsaid valves, said means being constructed and arranged to open saidinlet valve near the beginning of the intake cycle, and to close saidinlet valve at a point substantially after the end of said intake cycle,an intake conduit. a valve in said intake conduit anterior to the inletvalve, means for holding said valve in a flow restricting positionduring cranking of the engine, and means for moving said last namedvalve to inoperative position when the engine is running at normalspeed.

5. The method of facilitating diesel engine starting which comprises thesteps of controlling by throttling the induction of air to each cylindersolely in the period of engine cranking by substantially increasing airvelocity to the cylinder in the cylinder suction cycle, and timing theinduction to terminate by intake valve closing when ramming velocityinto the cylinder becomes ineffective for charging.

6. The method of facilitating starting of a diesel engine whichcomprises the steps of controlling by throttling the induction of air toeach cylinder separately and 'at least to two groups of cylindersthereof solely in the period of engine cranking by substantiallyincreasing air induction velocity to each cylinder during its suctioncycle and timing the induction to terminate by intake valve closing whenramming velocity into the cylinder becomes ineffective for charging.

7. The method of facilitating diesel engine starting which comprises thesteps of controlling by throttling the induction of air to each cylindersolely in the period of engine cranking by substantially increasing airvelocity to the cylinder in the cylinder suction cycle, timing theinduction to terminate by intake valve closing when ramming velocityinto the cylinder becomes ineffective for charging, and reducing theinduction velocity as the engine attains a normal running condition.

8. The method of facilitating diesel engine starting which comprises thesteps of controlling the induction of air to each cylinder in the periodof engine cranking by substantially increasing air velocity to thecylinder in the normal cylinder suction cycle, maintaining the intakevalve open 15 as the compression cycle begins, whereby a ramming effectis produced by the opposed motion of the high velocity intake air andthe direction of piston motion, and timing intake valve closing to occursubstantially simultaneously with termination of ramming velocity.

GEORGE R. ERICSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

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